 #define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <math.h>

int main() {
    float a, b, c;

    printf("Input a,b,c:");
    scanf("%f,%f,%f", &a, &b, &c);

    if (a + b > c && a + c > b && b + c > a) 
    {
        float s = (a + b + c) / 2;
        float area = sqrt(s * (s - a) * (s - b) * (s - c));
        printf("area=%.2f\n", area);
    }
    else {
        printf("It is not a triangle\n");
    }

    return 0;
}